Abstract: Apparatus for forming objects from molten material includes a mold frame and a movable mold side having complementary faces that define molding cavities. The mold frame includes a mold housing having an internally heated manifold which has a plastic distribution channel for feeding plastic to an injection nozzle passageway having a restricted discharge nozzle that discharges the plastic into a molding cavity. Within the injection nozzle passageway is a heater probe which has an internal heater, preferably an electrical cartridge heater. The probe is secured by an integral seating flange to the mold housing to hold the probe coaxially aligned in the injection nozzle passageway and to hold the probe against shifting with thermal expansion and contraction of the manifold.

Abstract: An improved device for making plastic articles from resin and an improved runner block assembly for a mold for making plastic articles from resin have been made by providing a runner block assembly having at least one channel wherein the channel has a cross-section with two opposite sides having a length substantially less than the two other sides thereby forming a thin, flat channel sufficient to provide shear resistance resulting from forcing resin through the channel; means for connecting the channel to a plurality of mold cavities, and means for supplying resin to the channel.

Abstract: This invention relates to an improved core ring gated injection molding system. The valve pin has a tip portion which joins a larger diameter stem portion at a tapered shoulder and extends through the cavity into the mold platen on the other side. The tip portion of the valve pin is substantially smaller in diameter than the gate through the cavity plate, thus providing for the flow of melt through the gate around it when the valve pin is in the retracted open position. In the forward closed position, the tapered shoulder seats in the gate to provide a seal. By providing for operation in reverse directions to previous core ring gated systems, this increases cooling to the mold platen in the closed position and decreases it in the open position.

Abstract: Undercut tubular synthetic plastic articles, such as fittings, are formed in the mold cavity of an injection molding machine on a one- or two-piece core a portion of which is surrounded by the undercut portion of the article and a first smaller-diameter portion at one side of the undercut portion. If the core consists of two components, a cylindrical component of the core slidably guides the aforementioned portion and is surrounded by a second smaller-diameter portion of the article at the other side of the undercut portion.

Abstract: This invention relates to a movel core ring gated injection molding system. Pressurized melt from a molding machine flows through the system and into a cavity. A gate leading to the cavity and a bore in the movable mold platen are in alignment and of the same size to receive the head portion of the valve pin which extends from a reduced neck portion. Actuating mechanism drives the valve pin between a retracted closed position to an open position in which the reduced neck portion extends into the cavity. In the closed position, the head portion of the valve pin extends a considerable distance into the bore in the mold platen to provide sufficient cooling to rapidly cool the melt in the cavity adjacent the pin. In one embodiment, the valve pin has a hollow portion adjacent the neck portion to provide the valve pin with thermal separation between the hot melt and the cool mold platen.

Abstract: This invention relates to hot tip bushing means for a synthetic resin injection molding machine, which can reduce the pressure loss at the injection molding time and determine the position of a heating tip easily and accurately. To attain this purpose, a straight resin flow passage is formed axially in a cylindrical body of the hot tip bushing means and the fused resin passing through the straight resin flow passage is heated by an outer heater. Further, a cylindrical body of the hot tip bushing means which is near the heating tip is fit to a mold sprue, thereby the position of the heating tip is determined easily and accurately.

Abstract: This invention relates to cap means for preventing resin from remaining in a mold of a runnerless injection molding apparatus. The cap means is of a frusto-conical profile and incorporated in a space formed adjacent to a front end of a heating cylinder. Further, the cap means is provided with an opening from which a pointed tip member of the heating cylinder can project. The invention aims at removing resin scorching, its thermal decomposition, inconveniences of color or material exchange or the like.

Abstract: A hot manifold system for use in the injection molding of plastics is disclosed wherein runner channel heating is accomplished by heat pipes disposed within the manifold adjacent to the runner channels contained therein. The manifold system is an elongated structure having a heat receiving portion and a runner containing portion such that heat input may be applied to the heat receiving portion at an accessible location relative to the mold and conveyed to the remainder of the manifold for uniform heating thereof by the heat pipes.

Abstract: An injection molding machine includes a platen having a plurality of regularly spaced mold element-receiving chambers adapted to receive any of a number of various mold elements substantially wholly within the stationary platen. A hot manifold system is included between the stationary platen and a plastics injector unit, which includes a plurality of blocks independently coupled to the fixed platen, each block having channels through which the plastics material can flow, the channels of adjacent blocks being coupled by a coupling unit. The machine is particularly designed for quick inexpensive mold changes, and has particular utility in laboratory testing of mold designs and small low-capacity production in satellite plants.

Abstract: The invention comprises a method and apparatus to quickly heat a mold cavity surface or portions thereof just prior to the injection of a foamable plastic resin. The apparatus comprises one or more thin metal surface sheets or bands of high electrical resistivity in the mold cavity covering those portions of the mold where a smooth surface finish on the product is desired. In an alternative form the surface sheets may be plated or sprayed metal of high resistivity on a layer of thin electrically non-conducting plastic in turn adhered to the mold cavity surface.The thin metal surface sheet is resistance heated approximately 300.degree. F. in a few seconds or less by a low voltage high current source of electric power just prior to the injection of the foamable plastic. The high current passing through the metal of high resistivity causes conversion of electrical energy into sensible heat very quickly to accomplish quick heating of the mold cavity surface sheet.

Abstract: A multiple hot runner injection bush for lateral tunnel gating, with a foot and a shaft heated by a heating element and a central hot sprue arranged therein, furthermore, with a heated nozzle head which contains radially extending injection channels. The technical problem of the invention is seen in the exact heat control and adjustment of the nozzle head if a plurality of mould nests is gated. The nozzle head is provided as a plate-like head and projects beyond the diameter of the shaft by a multiple distance of the diameter of the shaft (two times through five times). The nozzle head incorporates, at least, four radially extending injection channels. The nozzle head comprises a plane ring face, adjacent to the shaft, and an outer covering apron. A copper ring is attached on the ring face. The copper ring carries a spirally arranged high capacity coil heater.

Abstract: A method for the fabrication of a plastic preform suitable for use in the preparation of biaxially oriented hollow articles is described wherein the duration of the preform injection molding cycle is reduced, thereby enhancing the productivity of the injection molding step. This end is attained by injection molding and cooling, and supercooling and conditioning simultaneously at a single station of an injection molding machine at different positions within the station.

Abstract: Hot runner injection molding apparatus for coinjecting two thermoplastic materials sequentially through separate channels to form at least a two-layer sandwich material is provided. There is a valve means for instantaneously switching the flow of thermoplastic material from one channel to the other channel, the valve means preferably comprising a shuttle ball member.

Abstract: An improved device for making plastic articles from resin and an improved runner block assembly for a mold for making plastic articles from resin have been made by providing a runner block assembly having at least one channel wherein the channel has a cross-section with two opposite sides having a length substantially less than the two other sides thereby forming a thin, flat channel sufficient to provide shear resistance resulting from forcing resin through the channel; means for connecting the channel to a plurality of mold cavities, and means for supplying resin to the channel.

Abstract: This relates to an apparatus for injection molding preforms for beverage bottles wherein a minimum cycle time is involved. Cores over which thermoplastic material is injection molded to form preforms for use in the blow molding of bottles are provided in sets and carried by a rotary turret so that as soon as the injection molded thermoplastic material has sufficiently set to permit its transfer with its associated core out of an injection mold cavity, the apparatus may be actuated to remove first injection molded preforms and thereafter immediately present a new set of cores to the injection mold cavities. This provides ample time for the cooling of the preforms so that when removed from the cores they will not be unduly deformed. In accordance with the feasible use of the apparatus, plural preforms, on the order of twenty-four and greater, may be formed with a cycle time on the order of 10-12 seconds.

Abstract: Injection apparatus suitable for supplying in-mold thermoset coating material into a compression molding tool is provided, which injection apparatus comprises a housing (10) the forward end of which comprises an outlet nozzle (11) and an outlet channel (12) extending through the outlet nozzle, the forward terminus of the outlet channel being an outlet port (13). First and second material supply channels (14 and 15) extend within the housing from first and second supply inlet ports (16 and 17) in the housing, respectively, to a single common junction with the outlet channel. A shut-off rod (26) is slideably disposed within the outlet channel, being adapted to provide a sealing closure of the outlet port in a first, forward position and being retractable from the forward position to a second position in the outlet channel rearward of the junction of the material supply channels with the outlet channel.

Abstract: A hot sprue assembly is provided for controlling flow of molten material into the mold cavity of an injection molding machine. The hot sprue assembly is particularly designed for use with an injection molding machine for molding centrally apertured record discs, such as video information discs. The hot sprue assembly includes a hot sprue bushing cooperating with a generally conically-shaped dispersion head to define an open and relatively narrow annular gate through which molten material is injected into the mold cavity, and a central die plug within the mold cavity for cooperating with the dispersion head to mold a central aperture into the disc. Valving of the molten material through the gate is achieved by heating the sprue assembly to create a temperature differential which, during solidification of the material within the mold cavity, permits the material within the mold cavity to solidify up to the gate without substantial solidification of material within the sprue assembly.

Abstract: This invention relates to an injection molding process for synthetic resin and its apparatus which enable to produce highly precise molded articles and shorten the molding time. More particularly, by actuating a forcible cooling means disposed in a runner and extended into a gate, the fused resin in the gate is cooled and solidified locally, thereby the gate is closed. On the other hand, by stopping the forcible cooling means, the solidified resin in the gate is heated and fused by a heater mounted either inwardly of a runner or outwardly thereof.

Abstract: A mold apparatus for liquid injection molding machine which mold is dripless comprising a frame, four support posts mounted on the frame; a conduit for a liquid molding composition slightly mounted on the forward end of the frame having a front end and a rear end; a first plate means having passage means therein for the passage of the liquid molding composition and fixedly mounted on the forward end of said conduit and adapted to slide within support means and within said mold frame means located adjacent to the forward end of said frame, nozzle means at the end of said passage means of said first plate means at the rear end of said mold frame means and away from said conduit means and pin means slidably mounted in said mold frame means adapted to open and close said nozzle means and mold cavity means slidably mounted on said support means adapted to move toward and away from said nozzle means.

Abstract: This invention relates to an improved valve pin bushing for use in a multi-cavity valve gated injection molding system and a method of manufacture. Each valve pin bushing has a main body portion which is positioned between the end of a manifold plate arm and the heated nozzle, and a collar portion which projects from the main body portion with clearance beyond the end of the manifold plate arm. The melt passage 34 extending through the manifold plate joins a melt duct extending diagonally through the main body portion and the valve pin is snugly received in a bore in the bushing. The bore has an enlarged portion which receives the melt from the diagonal duct which then flows through the heated nozzle around the valve pin. The valve pin bushing has a peripheral flange which laterally locates it in the cavity plate to offset frictional forces from thermal expansion of the manifold plate.

Abstract: Screw feeder and ram injector units for injection molding presses are disclosed. The feeder and injector units incorporate several novel features including power extension and retraction of the feeder unit by the drive ram of the injector unit. The screw feeder unit is supported directly on the ram unit without the necessity of separate supports on the press frame. A ram drive piston and injector plunger are laterally supported by means supporting the drive assembly on the injector assembly. Temperature control of molding compound is afforded by fluid circulation in a block carried on the inlet area of the screw feeder and a jacketed outlet nozzle on the ram injector.

Abstract: A hot runner system for use in combination with plastics molding tools for injection molding of plastics material with injection from several sprues comprises a central inlet member, heated runners for distributing from the central inlet member plastics material to a number of sprue bushes in which heating cartridges are inserted. The sprue bushes are fixed by securing means to a platen and form, together with said platen and said inlet member, a stationary and mechanically rigid assembly wherein contact between hot parts of the sprue bushes and the platen occurs only in rotationally symmetrical contact surfaces. The heated runners are individually movable relative to said assembly, but such movements will not affect the positions of the sprue bushes or the central inlet.

Abstract: An injection nozzle for use in an injection molding apparatus including a generally annular base portion which supports a generally cylindrical hollow side wall portion. The hollow side wall portion terminates at its upper end portion in an inwardly beveled heat transfer control portion. The beveled heat transfer control portion terminates in an angled mating portion which is of complementary angle to the angled mating surface of an injection nozzle accepting recess in the injection mold portion of the apparatus. The injection nozzle structure provides for controlled heat transfer control from the sprue portion of an injection molded parison to prevent crystallization in the sprue portion of the parison.

Abstract: A process and a device for forming a tennis ball by the formation of two semispherical bowls in crude elastomeric material each having on its border a structural shape that is deformed by compression when the two semispherical bowls are pressed one against the other while a depressurization is effected in the joining zone of the two semispherical bowls on the outside of them.

Abstract: This invention relates to an improved valve pin for an injection molding system and a method of making the same. The elongated valve pin has a tip end portion which extends from a larger driven end portion into the flow of melt to the cavity. The elongated tip end portion is provided with a desired combination of strength and thermal conductivity by having a copper core inside a steel casing. The casing is made by brazing a tip end cap member to a hollow sleeve. A predetermined quantity of copper wire is then inserted into the casing and melted in a vacuum furnace to form an integral construction. The excess sleeve is then cut off and the end is brazed into a well in the driven end portion of the valve pin. The tip end cap member is then machined to provide a tip end of a desired shape.

Abstract: A mold apparatus which in addition to the other mold elements, has shuttle plate means adjacent to the nozzle means out of which the molding composition comes out of into the mold cavity, which shuttle plate means forms part of the mold cavity. The shuttle plate means are adapted to automatically take a finished molded part from the mold and remove it out of the mold apparatus. At the same time while the molded part is being taken out of one portion of the shuttle plate means, the other part of the shuttle plate means is being utilized to form a molded part.

Abstract: An injection moulding machine has a reciprocable and rotatable screw which is water cooled internally. This enables the temperature of the machine to be precisely controlled. This further enables the required plasticization of the resin granules with limited mixing of the same, so that multi-color effects can be achieved. FIG. 5 shows the waterways in the screw and the rotating supply connections.

Abstract: An injection molding apparatus includes an injector portion which includes a plurality of mold cavity modules each having a plurality of cavities cooled by fluid flowing through a plurality of cooling channels which communicates with a common coolant manifold. Each mold cavity module is supplied with molten plastic material by a separate manifold which consists of an elongated shell having an exterior surface defining at least one inlet sprue communicating with a source of plastic and a plurality of outlet gates each communicating with a cavity of the mold module, a tubular heating element positioned within the shell for heating the interior portion of the shell, and a plurality of runners extending from the inlet sprue to the outlet gates and spiral about the heating rod so that molten plastic material may flow from the inlet sprue through the runners to the outlet gates and receive heat energy from the heating rod.

Abstract: A hot sprue valve assembly is provided for controlling flow of molten material into the mold cavity of an injection molding machine. The valve assembly is particularly designed for use with an injection molding machine for molding centrally apertured record discs, such as video information discs. The valve assembly comprises a stationary valve body supporting a movable valve member for sliding motion toward and away from the mold cavity. The valve member includes a hot sprue bushing defining a heated flow path for passage of molten material toward the mold cavity, and a dispersion head carried by the bushing for directing the molten material to flow in a generally radially outward direction through gate passages with substantially uniform radial distribution into the mold cavity. In one position, the valve member is advanced into the mold cavity to align the gate passages with the mold cavity and thereby permit flow of the molten material into the mold cavity.

Abstract: The invention comprises a method to quickly heat a mold cavity surface or portions thereof just prior to the injection of a foamable plastic resin. The apparatus comprises one or more thin metal surface sheets or bands of high electrical resistivity in the mold cavity covering those portions of the mold where a smooth surface finish on the product is desired. In an alternative form the surface sheets may be plated or sprayed metal of high resistivity on a layer of thin electrically non-conducting plastic in turn adhered to the mold cavity surface.The thin metal surface sheet is resistance heated approximately 300.degree. F. in a few seconds or less by a low voltage high current source of electric power just prior to the injection of the foamable plastic. The high current passing through the metal of high resistivity causes conversion of electrical energy into sensible heat very quickly to accomplish quick heating of the mold cavity surface sheet.

Abstract: A novel method and device for precision injection molding is disclosed providing controlled cooling of a portion of the mold cavity surface during the molding cycle, or several such portions independently, and also, in the preferred embodiment controlled heating of a portion of the mold cavity surface during the molding cycle or several such portions independently, whereby high quality, high precision parts having close dimensional tolerances may be produced. Another aspect of the invention, a volume-controlled variable conductance heat pipe is disclosed, which novel heat pipe comprises housing means forming a sealed chamber, fluid, such as water or ammonia, within the chamber, wicking means and control means for controling the thermal conductance of the heat pipe comprising means for controlling the volume of fluid in the liquid phase in the chamber.

Abstract: The invention relates to an injection mechanism for molding plastics, comprising at least one injection bushing, at least one lower needle valve, which is supplied by the injection bushing with molten plastics and opened by the pressure of the molten plastics during injection, further comprising heating means and cooling means adjacent to the flow path of the plastics, control means for maintaining the plastics at an adjusted temperature, further control means for injecting the molten plastics into at least one mold cavity via a corresponding injection aperture, and for the closing off the mold cavity after finishing the injection, wherein for improving this mechanism, especially for facilitating very small distances between injection openings, only one plunger within a heated distributor block is provided, which actuates several needle valves, situated at different locations within the distributor block, for supplying the molten plastics to the mold cavity via one single injection bushing, an injection nozzl

Abstract: The apparatus of the present invention includes a stationary assembly and a movable assembly. The stationary assembly is comprised of a stationary platen which has a heat plate, a temperature-controlled sprue bushing and a mold face positioned thereon. The movable assembly is comprised of a movable platen which has a heat plate mounted thereon and a mold face, corresponding to, and adapted to be aligned with, the mold face on the stationary assembly to form a partially open mold cavity. Means are provided to feed a supply of thermosetting molding material through the sprue bushing into the partially open mold cavity. Means are provided to completely close the mold cavity and place the apparatus in a compression stage.

Abstract: The apparatus of the present invention includes a stationary assembly and a movable assembly. The stationary assembly is comprised of a stationary platen which has a heat plate mounted thereon, a temperature-controlled sprue bushing mounted in the heat plate and a plurality of mold faces positioned on the heat plate surrounding the periphery of the sprue bushing. The movable assembly is comprised of a movable platen which has a heat plate mounted thereon and a plurality of mold faces, corresponding to, and adapted to be aligned with, the mold faces on the stationary assembly. Means are provided to move the movable assembly into close proximity with the stationary assembly to form partially open mold cavities. Means are provided to feed a supply of thermosetting molding material through the sprue bushing into a manifold area and into the partially open mold cavities. Means are provided to completely close the mold cavities and place the apparatus in a compression stage.

Abstract: Disclosed is a method and apparatus for forming multi-directionally oriented plastic articles by accumulating a body of plasticized thermoplastic material in an amount at least sufficient to form the desired article, and advancing the material under pressure from said body forward and through an orifice. The material is non-linearly sheared while being advanced from the body toward the orifice and prior to its issuance from the orifice to induce orientation stresses into the material, and during shearing the material is at a temperature which is conducive to orientation. The orientation stresses are frozen into the material when the material is formed to a desired configuration exteriorly of the orifice by known plastic forming techniques, such as extrusion, blow molding, injection molding, compression molding, thermoforming and the like. During such forming, additional orientation stresses may be induced in the material and superimposed upon those stresses previously introduced thereinto.

Abstract: Apparatus for injection moulding thermoplastic material is disclosed wherein a heavy-duty sprue bush is heated along a substantial portion of its length to keep the thermoplastic material from solidifying during interruptions in the moulding cycle. The apparatus provides for minimal contact between the heated sprue bush and the moulding die to prevent heat transfer between them. This is achieved by maintaining an air gap between the bush and the die except at points where the thermoplastic material passes into the moulding cavity. Sprue runners oriented generally parallel to the mould joint line are aligned with cavity injection openings which are similarly oriented. These injection openings pass through a thin wall of the mould that extends generally perpendicularly to the joint line such that when the moulds are open, the sprue is cleanly severed from the moulded article.

Abstract: This invention relates to an edge gated injection molding system. An electrically heated sprue bushing is seated in a well in the cavity plate with a centrally extending melt runner passage which branches radially outward with separate channels leading to a number of edge gates in the cavity plate. An air gap is provided to insulate the hot sprue bushing from the surrounding cooled cavity plate and a hollow seal is provided at each gate to convey the melt across the air gap. Each seal is in alignment with one of the channels and one of the gates, and has its inner end seated in a recess in the sprue bushing and its outer end abutting against the curved wall of the cavity plate. The outer ends of the seals are dome shaped so that they are slightly resiliently deformable. A portion of the wall of the cavity plate is slightly inwardly tapered so that at the gates, the effective combined diameter of the sprue bushing and the seals is slightly larger than that of the well.

Abstract: A hot sprue valve assembly is provided for controlling flow of molten material through a hot sprue bushing of an injection molding machine. The valve assembly is particularly designed for use with an injection molding machine for molding centrally apertured record discs, such as video information discs. The valve assembly includes a poppet valve movable between an open position to allow flow of molten disc-forming material into a mold cavity, and a closed position to prevent flow of the disc-forming material into the mold cavity. The poppet valve is designed to mold a central aperture in the disc upon movement to the closed position, and the valve assembly is designed to accommodate air ejector apparatus for removing a solidified record disc from the machine.

Abstract: A novel method and device for precision injection molding is disclosed providing controlled cooling of a portion of the mold cavity surface during the molding cycle, or several such portions independently, and also, in the preferred embodiment controlled heating of a portion of the mold cavity surface during the molding cycle or several such portions independently, whereby high quality, high precision parts having close dimensional tolerances may be produced. Another aspect of the invention, a volume-controlled variable conductance heat pipe is disclosed, which novel heat pipe comprises housing means forming a sealed chamber, fluid, such as water or ammonia, within the chamber, wicking means and control means for controlling the thermal conductance of the heat pipe comprising means for controlling the volume of fluid in the liquid phase in the chamber.

Abstract: Apparatus for producing hollow plastic articles in a hollow die with a relatively smaller reciprocating punch therein. Plastic material is fed from a nozzle aligned with the die, into the die about the punch, the punch being initially advanced into the opening of the die and retracting as the plastic is introduced from the nozzle. When the plastic introduction is completed, then the nozzle is slid laterally on the die until the duct of the nozzle is out of registry with the die and the nozzle thus closes the die. Then the punch is advanced within the closed die to compress the plastic material into the space between the die and the punch.

Abstract: An improved injection molding apparatus for molding parts of thermosetting plastic material. First and second mold portions which together form a mold cavity at their molding surfaces are heated to allow thermosetting plastic material to set within the mold cavity when under pressure. A fluid distribution member comprises a manifold having an inlet port, two or more spaced outlet ports and a passage interconnecting the inlet port with the outlet ports guides the flow of plastic material therein. The manifold is cooled and includes a first manifold section disposed within a channel formed at the upper surface of a second manifold section such that the interconnecting passage is formed by a first wall portion of the first manifold section and a second wall portion of a second manifold section within the channel. The first and second manifold sections are separable to permit access to the passage to permit cleaning thereof.

Abstract: This mould assembly for elastomers is of the type comprising a center block whose temperature is regulated. The block has means for injection of the elastomer into each mould cavity fed with elastomer by a nozzle of the injection device of the press. The center block has projections which are mounted on the block, or are part of the same material as the block, and project from two of opposite sides of the block. Small nozzles for directly injecting the elastomer into the mould cavities are detachably secured on the ends of the projections and adapted to cooperate with adjacent sections of at least two moulds in two or more sections which are disposed on the opposite sides of the center block. Means distinct from those of the block are provided for separately controlling the temperature of the projections and of the small nozzles. Means are provided for controlling the flow through the small nozzles. Means are provided for compensating for the expansion of the block and the moulds.

Abstract: A double nozzle injector system includes a manifold block with an internal conical sealing surface which receives an external conical sealing surface of a spindle coupling connected to an extruder for receiving molten plastic into an axial passageway terminating at a main outflow passageway extending transversely through the coupling. An annular flushing groove encircles the coupling with a plurality of angularly spaced radial flush passageways of small diameter extending between the annular flush groove and the interior of the coupling at the main outflow passageway. Runners in the manifold block are provided with plugs having spherical surfaces for directing flow to a pair of nozzle members attached to the manifold block. Upper and lower portions of the manifold block are controlled by separate heaters and thermostats.

Abstract: An improved molding apparatus for injection-compression molding thermosetting materials is described. The apparatus comprises a stationary platen assembly, a moveable platen assembly and a feed nozzle assembly.The stationary assembly is comprised of a stationary platen member, a heated plate mounted on the support plate and a plurality of mold faces mounted on the heat plate.The movable assembly is comprised of a moveable platen member, a heated plate mounted thereon and a plurality of mold faces mounted on the heat plate aligned with the mold faces on the stationary assembly.The feed, or injection, nozzle assembly is comprised of a cylindrical nozzle member, having an internal temperature controlling means, and a plurality of feed outlets positioned on the periphery.

Abstract: An injection molding machine includes complementary mold members which cooperate to present a mold cavity in the shape of a clay pigeon or other articles. An injection passage leading to the mold cavity receives a slidable pin of smaller diameter than the passage. The pin has a tapered tip which, when the pin is extended by a power cylinder, seats in an outlet opening of the passage to block the opening in a manner to prevent the formation of a sprue on the part. The pin is heated along with a surrounding sleeve to maintain the material in the passage in a molten state and to assure proper release of the part from the mold. When the pin is retracted, molding material is able to flow around it, through the injection passage, and into the mold cavity.

Abstract: A nozzle device used for injection-molding plastic products. In the present nozzle device, the hot runner may be formed into a block and set to a mold clamping mechanism irrespective of cavity mold. The device comprises a hot runner block of fixed length having a plurality of nozzles at one side thereof and a sprue at the other side thereof, the nozzles and the sprue being placed in communication with each other by the runner, and a base plate having a plurality of support plates. The nozzles may accessibly come into contact with gates of a cavity mold. In this device, no overheating occurs in the periphery of the gates of the mold.

Abstract: A nozzle for the injection of liquefied plastic material into the gate of a mold cavity has a tubular metallic body forming a sprue, the outer surface of this body being in contact with an annular heater in the shape of a closed shell whose interior is filled with a matrix of compacted MgO powder having one or more resistance wires embedded therein. The heater is held in position by a nut, threaded onto a gate-side extremity of the body, against a shoulder or a tapering surface portion thereof and is separated by an air space from a surrounding supporting structure.

Abstract: An injection gate of a mold cavity comprises an elongate valve rod which passes axially through a flow channel for molten plastic material and is guided in an extension of a thin-walled steel cylinder open at its opposite end toward an adjoining manifold plate. The rod extremity remote from the gate is secured to a tubular neck of a piston inside the cylinder whose stroke length is a fraction of the axial height of the cylinder's interior, a clearance around this neck providing space for drooling plastic while the length of the neck and of the peripheral cylinder wall serves for thermally insulating the manifold plate from the flow channel.

Abstract: A sprue bushing for an injection molding machine comprising a body surrounding a core. The core has a central passageway for flow of the plastic from the nozzle of the machine to the mold and has on its exterior surface longitudinal grooves. Assembly of the body and core forms fluid channels with the grooves. The temperature of the bushing is controlled by the flow of water through the channels.

Abstract: Heated material is injected into an annular cavity, defined by a pair of mold halves, through a sprue passage, defined by a sprue bushing and an end portion of a punch. The annular cavity and the sprue passage form, respectively the centrally apertured part and a sprue. After partial cooling of the heated material, the punch is locked in place while the annular cavity is displaced relative to the sprue passage so that the sprue is severed from the part along the peripheral surface of the punch end portion. The mold halves are separated to open the annular cavity while the sprue is resting on the punch end portion, and while the part is held by the punch end peripheral surface. After the mold halves are separated, a sprue ejector member is actuated to eject the sprue from the punch end portion. The finished video disc is then removed, carried by the moving platen of the moving mold assembly.